THE LATEST CHAMPION OF A GLACIAL AGE.* WE doubt very

much whether this book ought ever to have been published; its author, an acute and clever observer who had travelled widely, was frank and courageous in opinions and very industrious, and had given promise of a remark- able career as a geologist. A tragical end, when he was still young, made the world poorer, and deprived a good many people of a kind, soft-hearted, and genial friend. It was natural that his widow should wish to perpetuate his name in something more substantial and lasting than • Papers and Notes on Nu, Glacial Geology of Great Britain and Ireland. By the late H. 0. Lewis, ILL, P.G.S. Edited, from his Unpublished MSS., with an Introduction, by H. W. Orosskey, LL.D., F.G.S. London : Lougmans and 0o. half-a-dozen memoirs hitherto only published in abstract, and which contain much of promise, but were largely tentative and immature. Such experiments are not always wise in a world over- crowded with books. This conclusion is not ours only. The editor of the work, who has himself since died, speaks of the author's "uncompleted investigations" and of his book as "recording the phenomena he observed, the theories he tentatively formed from time to time, for the purpose of grouping the facts to- gether, and giving direction to his studies; the grounds on which one theory was abandoned, and another put to the test, very probably to be discarded in its turn, as fresh fields and pastures new' were visited." He says "the maps are as =- revised as the papers," and that Professor Lewis himself would not have published the volume as it stands. These confessions involve some responsibility upon those who have republished so much that is crude. More especially is this the case when we have the additional confession that "it is no secret that some of Professor Lewis's theories, so far as they have been understood by those who heard the papers he read before the British Association, and by those who had oppor- tunities of conversing with him, have not met with general acceptance among English geologists."

Assuredly, there is little time enough in these crowded days to read even the established results of long observation and close induction, and a book which cannot pretend to either claim cannot possibly enhance a reputation largely based upon promise rather than performance. The book does its pub- lishers infinite credit. It is printed on beautiful paper, in the clearest of type, and nothing could be better in their way than the admirable maps with which it is illustrated. When we turn to its matter, we are at once struck with a want of proportion, the five more or less completed papers, hitherto only published in abstract, and which alone contain Mr. Lewis's thought-out results, occupy only seventy-eight pages out of a total of five hundred and fifty,—not so many as those devoted to Dr. Crosskey's introduction, which is an interesting piece of work by an experienced writer on glacial geology, whom we have recently lost. It is scarcely more than double an appendix in which Mr. Percy Kendall has set out his own view on glacial matters, which, however interesting in themselves, cannot be said to illuminate Mr. Lewis's theories and opinions. The rest of the book, consist- ing of three hundred and fifty pages, is merely a reprint of the rough note-books which, like every other geologist, Mr. Lewis kept, and consist of a mass of disintegrated observa- tions, references, and opinions, most of the latter being °biter dicta. There is no clue by which to thread this tangle ; no index,—nothing, in fact, but a geographical distribution of the information. No doubt this, the largest part of the book, contains many shrewd remarks, many references to forgotten writings, and many valuable notes; but they are all un- digested, and we can only regret that the architect who brought together so many materials for his building should not have had the privilege of putting them together in a form that his readers could understand and appreciate. As it is, we feel as if we were taken into a stoneyard piled with stones, some in their original rough state, and some partly hewn; but where we are nowhere certain that we have any one stone carved and finished as the author would like us to have seen it. If the professed geologist may be able to glean valuable facts and valuable inferences from a patient reading of the book, it will not, we fear, prove very attractive to the general reader, who may, in fact, be often misled by emphatic utter- ances upon what are, after all, matters of opinion. Mr. Lewis's observations cover considerable ground, and include America, Switzerland, and Italy, as well as Britain ; but it is chiefly to the last, and particularly to the less-known districts west of the Pennine chain and to Ireland, that the bulk of his remarks are directed.

The most important and distinctive conclusion for which Mr. Lewis fought, and with which his name is much connected, is not so popular now with writers on glacial matters, namely, that the facts support not a general submergence, but the action of great ice-sheets moving not only over the land, but over sea-basins like the North and the Irish Seas, scooping up their bottoms, and carrying pebbles and fragmentary shells to places many hundreds of feet high. This theory is a good touchstone of his methods. It does not seem to strike him as in any way necessary, before postulating the movement of great masses of ice up and down hill, in and

out of great ocean cavities, and up long and rapid slopes for many hundreds of feet, that it is his duty first to establish the capacity of ice to do such work,—to explain how ice, which must crush under a comparatively small pressure, can carry a sufficient thrust to enable it to move in this way, and if it could thus move, whence such a thrust is to be derived. The whole argument seems to be built up in cloudland, and not to be a scientific induction at all. Similarly, it seems incredible that any one knowing glaciers as they actually are and actually work, can speak of ground moraines as phe- nomena closely akin to the till and drift of Northern Europe and America.

That glaciers can and do move sporadic boulders under- neath their feet is a well-ascertained fact; that a glacier or any great mass of ice can move the gigantic cushions several hundred feet thick of heterogeneous soft materials which gather underneath it as it goes along, is a postulate which ought never to have been imported into science unless and until it had been verified by observation,—a verification which the experience of such a well-known explorer of glaciers as Dr. Bonney shows to be impossible. On some matters Mr. Lewis's conclusions seem to us much more rational. They will not, however, be very welcome to the champions of extreme glacial views. Thus, he is an opponent of the glacier erosion of lakes, on which subject he writes :—

"Every lake that I have seen in Switzerland is due to the dam- ming up of old valleys by moraine drift. The drift-dam of the Interlaken lakes occurs to the west of them ; that of Sargen Lake is north of Sargen ; that of the Lake of Lucerne is north of Lucerne; that of Lake Zurich is in the town of Zurich. I have seen no evidence of glacier excavation."

He is an opponent, also, of so-called inter-glacial periods, and says :—

" The lignite beds of Utznach and DUrnten, supposed to indicate a warm inter-glacial epoch, are, in reality, pre-glacial, and corre- spond with the pre-glacial forest bed of the coast of Norfolk, of quarternary or pleistocene age. Of variations in the glacial epoch, or steplike advances and retreats of the old glaciers as well as the present ones, there is plenty of evidence ; but of more than one great extension of the ice, or of any extension beyond the terminal moraines, I found no trace."

Mr. Lewis also did something, and might have done more if he had lived, to limit the ice-sheets, and to substitute for them local glaciers; thus he writes :—

"It has also been stated that the Black Forest was covered by an ice-sheet of indefinite boundaries. I found, however, that the glaciers of the Black Forest were small, and were as precisely limited by moraines as are the glaciers of the Vosges, of Wales, of Killarney in Ireland, and of the Rocky Mountains of America."

In England, also, he considerably limits the area supposed to have been occupied by the ice-sheet, and says ;—" The great glaciers of England can be as sharply distinguished from one another as the ancient glaciers of Switzerland."

While he is a firm believer in an ice-sheet having overwhelmed the Irish Sea and overridden the Isle of Man and Anglesey, and extended as far as Bray Head in Ireland, he allows that Wales supported three distinct and disconnected systems of local glaciers, one radiating from Snowdon and the Arenig district, another from the Plynlimmon district and the mountains of Cardiganshire, and a third originating among the Brecknockshire Beacons. The ice-stream from each of these centres, he allows, transported purely local boulders and formed well-defined terminal moraines. He says that all

Eastern England, south of Whitby, appears to be non- glaciated. On the other hand, all England, north of Stainmoor

Forest and the River Tees, except the very highest points, was smothered in a sea of solid ice. He contests the theory of a prolonged submergence of any part of Britain greater than about 450 ft., and he attributes the drift phenomena over Central and Southern England to the action of fresh-water streams and marine currents, and concludes that by far the larger part of England was not covered by land-ice.

The most remarkable concession, however, to the views of a very different school of geologists, is contained in the following pronouncements, which, considering Mr. Lewis's reputation for experience and skill, is as unexpected as some of Professor Prestwich's recent writings. Speaking of the wide-spread gravels, he says :— "I am not more fond of catastrophes than Sir Charles Lyell was. I have done my beat to accept a theory for the English gravels which would simply require a gradual marine sub- mergence, but I have been entirely unable to make the facts fit the theory. I find the writings of those who first studied phe- nomena nearest the truth. I find with them reliquice diluvisfue and debAcles, but not quiet submergence. I agree with them that a sudden and mighty rush of water swept across the country and then was over. I sympathise with those who believe that a convulsion of nature occurred at that time."

This is courageous, and, like some other concessions contained in the book, leads us to think that if Mr. Lewis had lived a few years longer, he would have modified a good many more of his views. He would possibly have been found ranging himself with that increasing body of scientific men, in fact, who are- revolting against the extravagances into which geology has-

been dragged in recent years by some influential writers who- command a picturesque style, and have largely substituted imagination for induction in the cultivation of a fascinating science.